The refractive characteristics of an individual's eyes are magnitudes that play an essential role in preparing a pair of eyeglasses for correcting that individual's vision.
Various methods and devices are presently known for determining the refractive characteristics of an eye of an individual. They are based in particular on the photorefraction technique and on a so-called “skiascopy” technique.
Nevertheless, those methods and the associated devices are time-consuming to implement.
The manual devices with which an observer observes said retinal reflection with the naked eye are not very accurate. Accuracy is improved by using a detector, but the measurements take a long time to perform, since each of the individual's eyes needs to be measured individually: only the retinal reflection from only one of the two eyes of the individual is observed at any one time.
In addition, known devices include constraining means for imposing a predetermined posture on the head and/or the eyes of the individual in a frame of reference associated with the image capture device, e.g. by means of a rest for the forehead and by means of a chin support, and/or means for constraining the gaze direction, e.g. by having a target for the individual to gaze at.
The measurements of refractive characteristics performed using such existing methods and devices are therefore not performed under natural conditions concerning the posture and the gaze direction of the individual, and therefore do not enable the individual's binocular vision to be taken into account.
For example, those measurements do not make it possible to determine the refractive characteristics of an individual's eye under near or intermediate vision conditions.
Unfortunately, the refractive characteristics of an eye may change significantly depending on vision conditions, on the task to be performed by the individual, and on the individual's posture and gaze direction.